Organo bimetallic compounds



Unite tates Patent Ofitice 3,%9,445 Patented Dec. 18, 19%2 3,969,445@RGANU .BEMETALLEC CEEMPUUNDd Richard D. Gorsich, Eaton Rouge, 1121.,assignor to Ethyl Corporation, New York, NHL, a corporation of Delaforother purposes.

The compositions of this invention are organo bimetallic compounds ofthe general formula In this formula R is a cyclopentadienyl or alkyloracylsubstituted cyclopentadienyl group containing from 5 to about 18carbon atoms, or is an indenyl or fluorenyl group; R is a hydrocarbongroup, preferably an alkyl, aryi, cycloalkyl, arailtyl, alkaryl, oralkenyl radical containing from 1 to about 18 carbon atoms; M is anelement of group lV-A of the periodic system having an atomic numberfrom 14 to 82, inclusive, i.e., silicon, germanium, tin or lead; M is anelement of group IV-B, V-B or Vl-B of the periodic system having anatomic number from 22 to 74, inclusive, i.e., titanium, zirconium,hafnium, vanadium, niobium, tantalum, chromium, molybdenum or tungsten;a is 4 when M is a group IVB metal and is 3 when M is a group V-B orVI-B metal; bisl,2or3;cis1,2or3;thesumof2bandcis4 when M is a group V-Bmetal and the sum of b and c is 4 when M is a group IV-B or Vl-B metal;and d is 2 when M is a group V43 metal and is 1 when M is a group lV-Bmetal or VI-B metal.

compositions of this invention are, in general, liquid or low-meltingsolid compounds which are stable at ordinary temperaturesand which canreadily be prepared and stored without special precautions for futureuse. The lead compounds melt, in general, at lower temperatures than thecorresponding tin compounds and the melting points tend to increase withthe number and molecular weights of the organic substituents designatedabove as R.

These compounds vary in color from white through yeliow to orange. Thedepth of color tends to increase with the atomic weight of the group IVAmetal and with the number of the group IV-B, VB or VI-B metal carbonylgroups in the molecule.

The compounds of this invention in general are soluble in organicsolvents such as aliphatic and aromatic hydro carbons, e.g., n-hexane,petroleum naphtha and benzene, in alcohols such as ethanol and hexanol,in halohydrocarbons such as methylene dichloride and carbontetrachloride, in others such as diethyl ether, methyl ethyl ether andtetrshydrcftn'an in mixtures of foregoing.

Of the metals represented by M in the above formula, lead is preferredfor several reasons. It is readily separated from its ores, is availablein large quantities and is considerably cheaper than the other metals.Consequently, the lead compounds of the invention are more adapted forpreparation on a larger scale thereby taking advantage of the economiesnormally associated with large scale operations.

The novel compounds of this invention are of value in the chemical andallied arts. For example, the lead compounds are potent antiknoclcagents and in this utility they are versatile agents in that they arehighly efiective group having up to 8 in both unleaded and conventionalleaded gasolines made from a wide variety of base stocks. Of thecompounds encompassedby this invention, those containing both lead andvanadium are preferred as antidetonants because of the powerfulantiknock effects produced thereby. The most outstanding 'antiknocks arethe dialltyllead cyclopcntadienyl vanadium tricarbonyls, especiallythose compounds in which the alkyl groups are methyl or ethyl or acombination of these.

Thus, gasoline fuel compositions containing the novel compounds of thisinvention in amounts sufficient to increase the antiknock rating thereofand, in particular, those containing a dialkyllead cyclopentadienylvanadium tricarbonyl, are highly effective fuels for internal combustionengines, the use of which is characterized by smoothness of engineoperation.

That the compounds of this invention are highly versatile is shown bythe fact that their use as antiknock additives not only involvesclear-i.e., unleadedfuels but includes leaded fuels as well, that is,fuels containing a previously known allcyllead antiknock compounds suchas tetraethyliead or containing a mixture of such alkyllead compounds.Thus, a liquid hydrocarbon fuel for Otto cycle engines containingantiknock-increasing amounts of both a tetraalkyllead compound and alead-containing compound of this invention is superior in antiknockeffectiveness to the same fuel containing a like amount of either ofsaid compounds in the absence of the other. Best results occur when theconcentration of the tetraalizyllead compound is equivalent to fromabout 0.5 to 6.0 grams of lead per gallon and the concentration of thecarbonyl compound is equivalent to from about 0.01 to 4.0 grams of leadper gallon.

The preferred antiknock fuels of the invention (because of their economyand availability) are leaded or unleaded gasolines containing a compoundof the formula wherein M is tin or lead; R is a cyclopentadienyl orlower alkylor acyl-substituted cyclopentadienyl group, e.g., methylcyclopentadienyl or acetyl cyclopentadienyl, or is an indenyl orfiuorenyl group, and R is a lower alkyl group, e.g., methyl, ethyl,pentyl, etc., or is an aryl carbon atoms, e.g., phenyl, tolyl, Xylyl,etc.

addition to their effectiveness as antiknock agents for hydrocarbonfuels, the compounds of this invention are excellent lubricantadditives. In this application, as well as in fuels, they exhibitunusual versatility. Thus, when dissolved in lubricants, theyeffectively improve the ricating properties thereof, greatly reduceengine wear, virtually eliminate frictional damage, and/ or bring aboutoverients in stability. Their versatility is further a .ested to by thewide variety of natural and synthetic lubricant bases in which theyproduce the above effects. For example, they are highly effective forthe above and other purposes in such lubricating and industrial oils ascrankcase lubricating oils, transformer oils, turbine oils,

transmission fluids, cutting oils, glass annealing oils, gear oils,mineral white oils, oils thickened with soaps and inorganic thickeningagents, hydraulic fluids and, in general, engine and industrial oilswhich are derived from crude petroleum or produced synthetically.

Typical of these synthetic lubricants are the polybutene oils, the esteroils, the silicone oils, phosphates, phosphonates and the like. Theester oils include such compounds as di-Z-ethylhexyl sebacate,di-sec-amyl-sebacate, di-Z-ethylhexyl azelate, di-3-methylbutyl adipate,di- Z-ethylhexyl adipate, diisooctyl adipate, di-Z-ethylhexyl phthalate,dibutoxyethyl phthalate, pentaerythritol tetracaproate, triethyleneglycol .di-Z-ethylhexanoate and d polyethylene glycoldi-Z-ethylhexanoate. Examples of the silicone oils are the dimethyl,divinyl, diphenyl, methyl vinyl, methyl pheuyl, diethyl, dibutyl,di-pbromophenyl, di-p-chlorophenyl, di-p-fiuorophenyl,di-m-trifluoromethylphenyl, di-p-phenoxyphenyl, di-m-chlorophenyl,di-3,4-dichlorophenyl, di-3-chloro-4-bromophenyl, di-pmethoxyphenyl anddi-p-cyanophenyl siloxanes, i.e., silicone derivatives.

Among the most effective compounds of this invention as lubricantadditives are those containing vanadium bonded to lead and particularlyto tin. Thus, these are the preferred lubricant additives for use inaccordance with this invention.

Accordingly, hydrocarbon lubricant compositions containing, in amountssufficient to improve the lubricating properties thereof, the novelcompounds of this invention wherein M is vanadium and M is lead or tinand, in particular, those containing a dialkyltin cyclopentadienylvanadium tricarbonyl, are effective lubricants for internal combustionengines and for other applications.

An excellent feature of these lubricant additives is that they can beused not only in a wide variety of oils but also in combination withother additives without in any Way impairing their eifectiveness or thatof the other additives. Such other additives include, for example,antioxidants, metal deactivators, detergents-dispersants, pourpointdepressants, viscosity index improvers, antifoam agents, corrosioninhibitors, oiliness or film strength agents, dyes and the like.

The preferred lubricants of the invention are the cheap and readilyavailable liquid hydrocarbon crankcase lubricating oils containing fromabout 0.05 to about 5.0 weight percent of vanadium as a compound of theformula wherein M is tin or lead, R is a cyclopentadienyl or lower alkylor acyl cyclopentadienyl group, e.g., methylcyclopentadienyl oracetylcyclopentadienyl, or is an indenyl or fluorenyl group, and R is alower alkyl group, e.g., methyl, ethyl, pentyl, etc., or is an arylgroup having up to about 8 carbon atoms, e.g., phenyl, tolyl, xylyl,etc.

In addition to the foregoing uses, the compounds of this invention findapplication as plasticizers and stabi lizers for vinyl and othersynthetic resins such as polyvinyl chloride.

The compounds of this invention are best prepared by reacting an alkalimetal derivative of a cyclopentadienyl or alkyl or acyl cyclopentadienylcarbonyl of a metal of group IV-B, VB or VLB of the periodic system(titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium,molybdenum or tungsten) with an organo metal halide of a metal of groupIV-A of the periodic system (silicon, germanium, tin or lead). In thisreaction, the alkali metal of the carbonyl reactant is replaced by theorganometallic radical of the halide reactant. The carbonyl reactantsused in this process are preferably alkali metal cyclopentadienyl oralkali metal alkyl or acyl cyclopentadienyl carbonyl compounds oftitanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium,molybdenum or tungsten having the formula RM co ,M

wherein R is a cyclopentadienyl or alkyl or acyl cyclopentadienyl group,or is an indenyl or fluorenyl group, M is titanium, zirconium, hafnium,vanadium, niobium, tantalum, chromium, molybdenum or tungsten, i.e., agroup IV-B, VB, or VI-B element having an atomic number of 22 through74, inclusive (Periodic Chart of the Elements, Fischer ScientificCompany, New York, 1957), M is lithium, sodium, potassium, rubidium orcesium, i.e., a group I-A element having an atomic number of 3 through55, inclusive, a is 4 when M is a group lV-B metal and is 3 when M is agroup V-B or VI-B metal, and e is 2 when M is a group VB metal and is 1when M is a group IV-B or VI-B metal. Of the group 4; LA metals, sodiumand potassium are preferred because of their availability, reactivity,and economy and, of the group IVB, V-B and VI-B metals (i.e., M),vanadium is preferred for the reasons noted above.

The halide reactants are mono-, dior triorganometal halide compoundshaving the formula wherein M is silicon, germanium, tin or lead, i.e.,an element of group IV-A of the periodic system having an atomic numberfrom 14 to 82, inclusive; X is halogen; f is 1, 2 or 3; and R is analkyl, aryl, cycloalkyl, aralkyl, alkaryl or alkenyl radical; andwherein the several R groups can be the same or different. Generallyspeaking, each of the R radicals contains up to about 18 carbon atoms.Of the halogens, chlorine is preferred because the organic chlorides ofM are generally more stable and more soluble in organic solvents thanthe bromides and iodides and are more reactive than the fluorides.Further, chlorine is the cheapest of the halogens and therefore, theorganic M chlorides are more economical to prepare than any of the otherhalides. In this process M is preferably tin or lead since the reactionproceeds very smoothly for these metals giving good yields of especiallyvaluable products.

In general, the halide groups of the halogen reactants are completelyreplaced by the cyclopentadienyl metal carbonyl groups of the carbonylreactant, one cyclopentadienyl metal carbonyl group being present in theformula of the product for each halogen atom originally present in thehalogen reactant. The reaction product may on occasion he a mixture ofmono-, diand trisubstitution products which can readily be separated bysolvent extraction, fractionation or other appropriate means.

The reaction of this invention is normally carried out in an inertorganic solvent. Ethers are generally preferrecl because of theirsolvent power for the reactants, and tetrahydrofuran is particularlypreferred because of the ready solubility of the reactants therein, itsvolatility and consequent ease of separation from the reaction productsand the ease with which the solvent may be made and kept anhydrous.

The reaction of this invention proceeds smoothly and rapidly atmoderately elevated temperatures, reaching completion for the reactionof lower alkyl derivatives of the group IV-A metal halides with carbonylreactants containing an unsubstituted cyclopentadienyl radical-in 15minutes to a half hour at 50100 C. Somewhat longer reaction times aredesirable for the higher alkyl and the substituted cyclopentadienylderivatives. The reaction temperature can vary from room temperature orbelow to the normal reflux temperature of the solvent or even higher ifpressure is employed. However, elevated temperatures should be used withcare since prolonged heating at reflux may cause some decomposition ofthe reaction product. The pressure employed may range from 10millimeters of mercury or less to atmospheres or more, but in general,normal atmospheric pressure is wholly satisfactory and preferred.

The invention will be more fully understood by reference to thefollowing set of illustrative examples in which all parts andpercentages are by Weight.

Example I A solution of 7.9 parts (0.03 mole) of molybdenum carbonyl,Mo(CO) and 3.2 parts (0.036 mole) of cyclopentadienylsodium in 200 partsof tetrahydrofuran was refluxed overnight. To the resulting yellowmixture, containing the so-formed cyclopentadienyl molybdenumtricarbonyl sodium, was added 3.6 parts (0.015 mole) of dimethyltindichloride. The mixture was briefly heated to reflux and then thesolvent was evaporated in vacuo. The residue was extracted withmethylene dichloride. The methylene dichloride extract was evaporatedand the residue was recrystallized from a mixture of methylenedichloride and n-hexane to give 2.6 parts (27 percent) of large yellowcrystals of dimethyltin bis(cyclopentadienylmolybdenum tricarbonyl)[CpivEo(CG) Snl\/i e melting with decomposition at 155-160 C.

Analysis.Calculated C 33.84, H. 2.53. 33.85, H 2.52.

Found C Example 11 When 6.95 parts of potassiummethylcyclopentadienyltitanium tetracarbonyl are reacted with 9.36 partsof triethyllead bromide in 730 parts of benzene at 50 C. for a period of15 minutes, methylcyclopentadienyltitaniurn tetracarbonyl triethylleadis obtained.

Example 111 Methylethylcyclopentadienylzirconium tetracarbonyl rubidiumand dibutylsilicon diiodide in the proportion of 9.9 parts of the formerto 4.9 parts of the latter are dissolved in 670 parts of toluene and arereacted at 80 C. for a period of 15 minutes. The product,bis(methylethylcyclopentadienylzirconium tetracarbonyl) dibutylsiliconmay be purified by recrystallization from anhydrous ethanol.

Example I V Dimethylcyclopentadienylhafniurn tetracarbonyl cesium (13.2parts) and n-octylgermanium trichloride (2.43 parts) are dissolved in700 parts of o-xylene. The mixture is stirred for 15 minutes at 85 C.The product is tris(dimethylcyclopentadienylhafnium tetracarbonyl)noctylgermanium.

Example V A mixture of 6.75 parts of diethylcyclopentadienyl- Vanadiumtricarbonyl dilitnium and 15.4 parts of di-ndodecyltin dibrornide isdissolved in 1000 parts of mixed hexancs and heated to reflux for a halfhour. The prodnot is the dimer of diethylcyclopentadienylvanadiumtricarbonyl di-n-d'odecyltin.

Example VI To 8.60 parts of butylcyclopentadienylniobiurn tricarbonyldisodium, 22.8 parts of dicetyllead diiodide is added and the mixture isdissolved in 1410 parts of nhexene. The solution is heated to reflux fora period of 1 hour. The dimer of butyicyclo-pentadienylniobiumtricarbonyl dicctyllead is obtained.

Example VH When 13 parts or" octadecylcyclopentadienylmolybdenumtricarbonyl sodium and 5 .2 parts of acetylcyclohexyl- -tin triiodideare mixed with 820 parts of petroleum naphtha and the mixture is heatedunder reflux for a period of 1 /2 hours.tris(octsdecylcyclopentadienylmolybdenum tricarbonyl)acetylcyclohexyltin is obtained.

Example X To 16 parts of octadecylmethylcyclopentadieny1tung-- stentricarbonyl potassium, 12 parts of triphenyllead chlo-- ride is addedand the mixture is dissolved in 1250 parts of ether. The resultingmixture is heated to reflux for hour. The product isoctadecylrnethylcyclopentadienyltungsten tricarbonyl triphenyllead.

Example XI 10 parts of didodecylcyclopentadienyltitaniurn tetracarbonyllithium is added to 4.6 parts of dibenzylsilicon dibrornide and themixture is treated with 660 parts of the diethyl ether of diethyieneglycol. Reaction for 1 hour at 80 C. results in the formation ofbis(didodecy1- cyclopentadienyltitanium tetracarbonyl) dihenzyl silicon.

Example XII 9.0 parts of methylbutylcyclopentadienylzirconiumtetracarbonyl sodium is reacted With a mixture of 4.6 parts ofphenethylgerrnanium triiodide and 620 parts of the dihutylether ofdiethylene glycol. The mixture is heated to C. and maintained at thattemperature for 1 hour. Tris(methylbutylcyclopentadienylzirconiumtetracarbonyi) phenethylgermanium is obtained.

Example XIII Tetrahydrofuran solutions of 11.1 parts of indenylhafniumtetracarbonyl potassium and 10.7 parts of tri-otolyltin chloride aremixed and the mixture is dissolved in 980 parts of tetrahydrofuran. Theproduct is indenyl hafnium tetracarbonyl tri-o-tolyltin.

Example XI V A mixture of 7.9 parts of fiuorenylvanadium tricarbonyldilithium, 14.4 parts of dixylyllead dibromide and 101 parts of benzeneis heated to C. for a period of 1 /2 hours. The dimer ofiiuorenylvanadium tricarbonyl dixylyllead is obtained.

Example XV A mixture of 8.3 parts of acetylcyclopentadienylniobiumtricarbonyl disodium, 10.3 parts of dicyclopentadienylsilicon diiodideand 840 parts of toluene is heated to 60 C. for a period of /2 hour. Theproduct is the dimer of acetylcyclopentadienylniobium tricarbonyldicyclopentadienylsilicon.

Example XVI 16.5 parts of octadecylcyclopentadienyltantalum tricaroonyldipotassium is added to a mixture ofbis(niethylcyclopentadienyl)germanium difluoride (6.7 parts) With 1080parts of o-xyiene and the mixture is stirred at C. for 1 hour. Theproduct is the dimer of octadecylcyclopentadienyltantalum tricarbonylbis(methylcyclopentadienyl) germanium.

Example XVII 5.2 parts of cyciopentadienylchromium tricsrbonyl lithiumis dissolved in 540 parts of mixed hexanes and the solution is mixedwith 6.9 parts or" bis(ethylpropylcyclopentadienyl)tin dibrornide. Themixture is heated to reflux for a half hour. The product isbis(cyclopentadienylchroniium tricarhonyl)bis(ethylpropylcyclopentadienyl tin.

Example XVIII When 7.1 parts of rnethylcyclopentadienylmolybdenumtricarbonyl sodium is reacted with 5.0 parts of methyllead triiodide in540 parts of n-hexane under reflux [or a period of 15 minutestris(methylcyclopentadienylmolybdenum tricarbonyl) methyllead isobtained.

Example XIX Ethylcyclopentadienyltungsten tricarbonyl potassium andtriethylsilicon chloride in the proportion of 10 parts of the former to3.8 parts of the latter are dissolved in 520 parts of methylenedichloride and are reacted at 60 C. for a period of 15 minutes. Theproduct is ethylcyclopentadienyltungsten tricarbonyl triethylsilicon.

Example XX Methylethylcyclopentadienyltitanium tetracarbonyl lith- 7 ium(6.9 parts) and dibutylgermanium difiuoride (2.81 parts) are dissolvedin 500 parts of n-octane. The mixture is stirred for a half hour at 60C. The product is bis(methylethylcyclopentadienyltitanium tetracarbonyl)dibutylgermanium.

Example XXI 8.0 parts of dimethylcyclopentadienylzirconium tetracarbonylsodium and 5.1 parts of n-octyltin triiodide dissolved in 590 parts ofpetroleum naphtha are heated under reflux for 1 hour. The product istris(dirnethylcyclo pentadienylzirconium tetracarbonyl) octyltin.

Example XXII A mixture of 11.3 parts of diethylcyclopentadienylhafniumtetracarbonyl potassium and 15.6 parts of tri-anaphthyllead chloride isdissolved in 1210 parts of diethyl ether and heated under reflux for oneand onequarter hours. The product is diethylcyclopentadienylhafniumtetracarbonyl tri-a-naphthyllead.

Example XXIII To 6.8 parts of butylcyclopentadienylvanadium tricarbonyldilithium, 6.8 parts of diallylsilicon dibromide are added and themixture is dissolved in 610 parts of the diethyl ether of diethyleneglycol. The solution is stirred for a half hour at 60 C. The dimer ofbutylcyclopentadienylvanadium tricarbonyl diallylsilicon is obtained ingood yield.

Example XXIV Octylcyclopentadienylniobium tricarbonyl disodium,divinylgermanium fluoride and the dibutyl ether of diethylene glycol arecombined in the ratio 102412880. The mixture is reacted at a temperatureof 60 C. for a period of a half hour. The product is the dimer ofoctylcyclopentadienylniobium tricarbonyl divinylgermanium.

Example XXV When 15.8 parts of cetylcyclopentadienyltantalum tricarbonyldipotassium and 10.7 parts of dimesityltin dichloride are mixed with1190 parts of tetrahydrofuran and the mixture is heated under reflux for1 hour, the dimer of cetylcyclopentadienyltantalum tricarbonyldimesityltin is obtained in good yield.

As stated above, the compounds of this invention are extremely useful asantiknock agents for internal combustion engine fuels. The followingspecific examples serve to illustrate the antiknock use of the saidcompounds.

Example XXVI A base stock is prepared by mixing 24 volumes ofisopentane, 66 volumes of isooctane and 10 volumes of cumene. To thisbase stock is added 0.75 gram of lead per gallon as a mixture (296.0parts) containing 5.5 percent of tetramethyllead, 24 percent oftrimethyL ethyllead, 37.5 percent of dimethyldiethyllead, 26 percent ofmethyltriethyllead and 7 percent of tetraethyllead. To the resultingmixture are added 79.1 parts (0.70 theory) of 1,2-dichloropropane and145.6 parts (0.775 theory) of ethylene dibromide. Finally, 0.15 gram ofmolybdenum per gallon as bis(cyclopentadienylmolybdenum tricarbonyl)dimethyltin is added. A significant increase in knock rating accompaniesthe final addition.

Example XX VII When the base stock of Example XXVI is treated with 1.2grams of vanadium per gallon as the dimer of diethylcyclopentadienylvanadium tricarbonyl didodecyltin, an increase inknock rating is observed.

Example XX VIII Atetraethyllead fluid is prepared by mixing 323.5 partsof tetraethyllead with 144.8 parts (0.60 theory) of nhexyl chloride and156.2 parts (0.625 theory) of mixed dibromotoluenes. The resulting fluidis mixed with a suflicient amount of a base fuel consisting of 15percent by volume of alkyiate gasoline and 85 percent of catalyticallycracked gasoline to give a lead concentration of 1.25 grams of lead pergallon. The addition to this blended fuel of 0.16 gram of titanium pergallon as ethylcyclopentadienyltitanium tetracarbonyl trimethyltinincreases the antiknock value thereof.

The following examples serve to illustrate the antiwear utility of thecompounds of this invention. All percentages given in these examples areby weight.

Example XXIX To the Mid-Continent oil of Example XXIX is added 1.5percent of bis(cyclopentadienyltitanium tetracarbonyl) dibenzyltin. Thisaddition results in a marked diminution in wear as tested by the 4-ballWear machine.

As indicated above, a wide variety of organo bimetallic compounds fallwithin the scope of this invention. Examples of these compounds are thefollowing: cyclopentadienyltitaniurn tetracarbonyl trimethylsilicon,bis(methylcyclopentadienyltungsten tricarbonyl) dibenzylgermanium, dimerof butylisooctylcyclopentadienylnobium tricarbonyl bis-2,4-xylyltin,tris(diethylcyclopentadienylzirconium tetracarbonyl) cyclohexyllead,dimer of fluorenylvanadium tricarbonyl dimesitylsilicon, indenylchromiumtricarbonyl triisobutylgermanium,bis(methylpropylcyclopentadienylhafnium tetracarbonyl) dicetyltin, dimerof cyclopentadienyltantalum tricarbonyl ditolyllead,tris(vinylcyclopentadienylrnolybdenum tricarbonyl) vinylsilicon,isobutylcyclopentadienyltitanium tetracarbonyl tri-n-octylgermanium,bis(isopropylcyclopentadienylchromium tricarbonyl) dicyclopentyllead,bis(butylisooctylcyclopentadienylzirconium tetracaroonyl)diethylsilicon, dimer of hexylcyclopentadienylniobium tricarbonyldiphenylgermanium, cyclopentadienylhafnium tetracarbonyl triphenyl ead,dimer of methylethylcyclopentadienyltantalum tricarbonyl divinylsilicon,and tris(fluorenyltungsten tricarbonyl) cyclohexylgermanium. Of theforegoing compounds, those wherein the group IV-A metal is lead or tin,the group V-B metal is vanadium and the organoradical iscyclopentadienyl or indenyl or a substitution product thereof arepreferred because of their ease of preparation and because of their higheffectiveness as antiknock and antiwear agents. Particularly preferredcompounds, for the reasons given above, include the dimer ofindenylvanadium tricarbonyl diallyltin,methylisooctylcyclopentadienylmolybdenum tricarbonyl trioctadecyltin andbis(methylcyclopentadienyltitanium tetracarbonyl) diphenyllead.

In making the valuable compounds of this invention, a wide variety ofreactants are available. The alkali metal simple or substitutedcyclopentadienyltitanium (or other group IVB, V-B or VIB metal) carbonylis made by the reaction of the appropriate inorganic metal carbonyl withthe cyclopentadienyl alkali metal compound in tetrahydrofuran or othersuitable solvent. The mixture is heated to reflux until the reaction isessentially complete. The reaction mixture is then used without furthertreatment for the reaction of the invention. Illustrative of thesecompounds are cyclopentadienylrnolybdenum tricarbonyl lithium,dibutylcyclopentadienyltantalum tricarbonyl disodium, fluorenyltitaniumtetracarbonyl potassium, methylethylcyclopentadienylchromium tricarbonylrubidium and octylcyclopentadienylzirconiurn tetracarbonyl cesium.

Methods for the preparation of organometal halides the other reactantsin the process of this inveution are described by E. Krause and A. vonGrosse ill Dlfi Chemie der MetalLOrganischen Verbindungen, Borntraeger,Berlin, 1937. Examples of such compounds include triphenyltin chloride,dimethyltin dichloride, triphenyllead chloride, diethyllead dichloride,dimethylsilicon difluoride, tris(ethylcyclopentadienyl)silicon iodide,bis(dodecylcyclopentadienyl) germanium dibromide, bis(ethylphenyl)tindichloride, and bis(acetylcyclohexyl)lead dibromide.

The reactants-RM(CO),M and R l\/l X -used in the preparation of thecompounds of this invention can be employed in proportions ranging froma 100 percent or greater excess of the group IVB, VB, or V'IB compoundto a 100 percent or greater excess of the group lV-A halide compound.Usually, they are employed in proportions corresponding approximately tostoichiometric equivalents but a moderate excess of onereactant or theother is oftenused to bring about an increased reaction rate.

Amon the criteria for the choice of solvents to be employed in thereactions of this invention are that the solvents be liquid under thereaction conditions and that they be inert to both reactants andproducts. Accordingly, the solvents may include, in general, aromatichydrocarbons such as benzene, toluene, the Xylenes and the like,aliphatic hydrocarbons such as hexanes, heptanes, octanes, petroleumnaphtha and the like, aliphatic or aromatic others such as dietbylether, diethylene glycol diethyl ether, diethylene glycol dibutyl etheror tetrahydrofuran, aliphatic alcohols such as methanol, ethanol,isopropanol, the pentanols, etc., and halohydrocarbons such as methylenechloride and carbon tetrachloride, and the like. The preferred solventis tetrahydrofuran because of its relatively high solubility for thereactants and for the other reasons mentioned above.

The reaction of this invention may be carried out at any temperatureWithin the normal liquid range of the solvent or at higher temperaturesif tLB liquid phase is maintained by the application of pressure. Thenormal reflux temperature is perfectly satisfactory in most instancesbut care should be taken not to employ too high a temperature for toolong a time inasmuch as excessive temperatures may cause more or lessextensive decomposition of the products. Thus, temperatures in the rangeof to 200 C. are employable, although best results are obtained between50 and 100 C., and this range is therefore preferred.

Because the reaction usually proceeds rapidly under reflux at normalpressure, atmospheric pressure is usually satisfactory but pressuresranging from millimeters of mercury to 100 atmospheres may be used ifdesired.

The reaction of this invention may be carried out under any atmosphereinert to both reactants and products. The lead and tin compounds arestable on exposure to dry air which can thus be used with safety. Theuse of dry nitrogen is preferred for the less stable germanium andsilicon compounds. Other suitable protective atmospheres include gaseoussaturated hydrocarbons such as methane and ethane and the noble gases,helium, neon, argon, krypton and xenon.

The normally solid compounds of this invention are soluble in and can bepurified by recrystallization from a variety of organic solvents.Specifically, simple aromatic solvents such as benzene or toluene,simple aliphatic solvents such as hexane, alcohols such as ethanol andhalohydrocarbons such as methylene chloride, and their mixtures, arefound to be satisfactory.

In the improved fuels of this invention, organic halide scavengers canbe employed. These scavengers can be either aliphatic or aromatichalohydrocarbons or a combination of the two having halogen attached tocarbon in either the aliphatic or aromatic portion of the molecule.These scavengers may also be carbon-, hydrogenand oxygen-containingcompounds such as haloallryl ethers, halohydrins, halonitro compoundsand the like. Still other examples of scavengers that may be used inthis invention are illustrated in U.S. Patents 1,592,954; 1,668,022;2,398,281; 2,479,900; 2,479,901; 2,479,902; 2,479,903; 2,496,983;2,661,379; 2,822,252; 2,849,302; 2,849,303 and 2,849,304. Mixtures ofdifferent scavengers may also be used. Concentrations of organic halidescavengers ranging from about 0.2 to about 2.5 theories based on thelead are usually sufficient although greater or lesser amounts may beused. Thus, in general, use is made of an amount of organic halidescavenger that is capable of reacting with the lead during enginecombustion to form relatively volatile lead halide and therebyeffectively control the amount of deposit formed in the engine.

The fuels of this invention can contain other additives. Typical ofthese are antioxidants (e.g., N,N'-di-sec-butylp-phenylenediamine;p-N-butylaminophenol; 4-methyl-2, 6-di-tert-butyl-phenol; etc.), metaldeactivators (e.g., N,N'-disalicilideue-1,2-diaminopropane, etc.), dyes,phosphorus additives (e.g., tri(/3chloropropyl)thionophosphate,dimethyltolylphosphate, dimethyl-xylylphosphate,phenyldimethylphosphate, tricresylphosphate, phenyldicresylphosphate,cresyldiphenylphosphate, trimethylphosphate, etc.), boron additives,corrosion inhibitors, detergents, antiicing additives, other antiknockagents (e.g., methylcyclopentadienylmanganese tricarbonyl,cyclopentadienylmanganese tricarbonyl, cyclopentadienylnickel nitrosyl,manganese pentacarbonyl, iron carbonyl, dicyclopentadienyliron, etc.),induction system cleanliness additives, top cylinder lubricants and thelike.

Having thus described the process and novel products 05 this inventionit is not intended that it be limited except as set forth in thefollowing claims.

I claim:

1. A compound represented by the general formula wherein R is a radicalselected from the group consisting of cyclopentadienyl,alkylcyclopentadienyl and acylcyclopentadienyl radicals containing from5 to about 18 carbon atoms, and of indenyl and fiuorenyl radicals; R isa radical selected from the group consisting of allryl, aryl,cycloalkyl, aralkyl, alkaryl and alkenyl radicals containing from 1 toabout 18 carbon atoms; M is an element selected from the groupconsisting of the elements of group IVB of the periodic system havingatomic numbers from 22 to 72, inclusive, the elements of group V-B ofthe periodic system having atomic numbers from 23 to 73, inclusive, andthe elements of group VI-B of the periodic system having atomic numbersfrom 24 to 74, inclusive; M is an element of group IV-A of the periodicsystem having an atomic number from 14 to 82, inclusive; :2 is 3 when Mis an element selected from the group consisting of the elements ofgroups V-B and VLB of the periodic system and is 4 when M is an elementof group lV-B of the periodic system; b is an integer from 1 to 3,inclusive, c is an integer from 1 to 3, inclusive; the sum of b and c is4 when M is an element selected from the group consisting of theelements of groups IV-B and VI-B of the periodic system; the sum of 2band c is 4 when M is an element of group V-B of the periodic system; anda. is 2 when M is an element of A 1. 1. which comprises reacting acompound represented by the general formula RM co ,,M

wherein a is 3 when M is an element selected from the group consistingof the elements of groups V-B and VI-B of the periodic system and is 4when M is an element of group IV-B of the periodic system, M is a metalof group I-A of the periodic system, e is 1 when M is an elementselected from the group consisting of the elements of groups IV-B andVIB of the periodic system, and is 2 when M is an element of group V-Bof the periodic system, and R is a radical selected from the groupconsisting of cyclopentadienyl, alkycyclopentadienyl andacylcyclopentadienyl radicals containing from 5 to about 18 carbonatoms, and of idenyl and fiuorenyl radicals, with a compound representedby the general formula wherein X is a halogen, R is a radical selectedfrom the group consisting of alkyl, aryl, cycloalkyl, aralkyl, alkaryland alkenyl radicals containing from 1 to about 18 carbon atoms, and fis an integer from 1 to 3, inclusive.

, wherein M is sodium and 6. The method of claim X is chlorine.

7. The method of claim 5, wherein M is tin. 8. The method of claim 5,wherein M is tin and M 5 is molybdenum.

9. The method of claim 5, wherein the reaction is carried out in anessentially inert organic solvent.

10. The method of claim 5, wherein the reaction is carried out in anether as solvent. 10 1]. The method of claim 5, wherein the reaction iscarried out in tetrahydrofuran as solvent.

References Cited in the file of this patent UNITED STATES PATENTS OTHERREFERENCES King et al.: Chem. and Industry, pp. 747-748 (June

1. A COMPOUND REPRESENTED BY THE GENERAL FORMULA